The Preparation And Properties Of PEDOT:PSS Composite Conductive Fibers

In recent years,the preparation of fibers from conductive polymers has become a research hotspot in the field of conductive fibers.In addition to the characteristics of electromagnetic shielding and antistatic of traditional conductive fibers,these fibers also have good flexibility and so on,which have great application value in the field of wearable smart textiles and flexible sensors.PEDOT:PSS can be dispersed in water,has high conductivity and its conductivity is kept at room temperature for several years without change.It is a conductive polymer with wide application and good development prospects.In recent years,although there are many reports of PEDOT:PSS fiber,there are still many problems.For example,PEDOT:PSS pure spun fiber has high conductivity but poor spinnability and poor elasticity;the fiber with elastomer as the main body,PEDOT:PSS as a conductive filler with good fiber elasticity,but poor conductivity due to uneven dispersion,which limits the application of fiber.In order to solve these problems,this study uses PEDOT:PSS as the main material,combined with its characteristics that can be dispersed in water,selects water-soluble sodium alginate(SA)and water-soluble polyvinyl alcohol(PVA),the PEDOT:PSS-based composite conductive fiber is prepared by using wet spinning method to impart higher deformation and elasticity to the PEDOT:PSS conductive fiber.The main research contents and conclusions are as follows:Firstly,PEDOT:PSS pure spun fiber was successfully prepared with acetone/isopropanol as the coagulation bath system,and the coagulation bath ratio was studied.The results show that when the volume ratio of acetone/isopropanol bath is 1:1,the prepared PEDOT:PSS fiber has better comprehensive performance,and its cross section is round and the surface is in good shape,the fiber tensile strength is 115±3 MPa,the elongation at break is 8.5±2% and the resistance is 38±2 k?/cm.Then,on the basis of the coagulation bath,the different chloride salt with different cation valence were added to study the effects of different ions and different amount of chloride salts added on the performance of PEDOT:PSS fibers.The results show that the mechanical and electrical properties of the prepared PEDOT:PSS fiber is better after adding LiCl in the coagulation bath.When the concentration of LiCl in coagulation bath reaches 0.06 mol/L,the fiber strength is increased to 185±7.5 MPa,the elongation at break is 9.5±1.5%,and the fiber resistance is reduced to 18±2 k?/cm.By adding LiCl to the coagulation bath,the spinnability and strength of the PEDOT:PSS fiber were improved,but the elongation at break of the fiber was low and the elasticity was lacking.Therefore,the water-soluble SA was mixed with PEDOT:PSS,and the PEDOT: PSS/SA composite fiber was successfully prepared.The fiber is improved in fiber formability and can be continuously spun several meters,and the fiber thickness is uniform and the surface is smooth.By XRD test,the pure PEDOT:PSS fiber has no crystallinity.With the increase of SA content,the crystallization degree of the composite fiber gradually increases to 22.5%.The mechanical properties of the fiber were tested.It is found that when the SA/PEDOT:PSS mass ratio is 0.6:1,the tensile strength increases from 185±7.5 MPa to 192±3 MPa and the elongation at break is increases from 9.5±1.5% to 15±2.3%.When the SA/PEDOT:PSS mass ratio is 1:1,the tensile strength of the fiber is increased to 203±2.8 MPa,and the elongation at break is increased to 28±2.5%.The amount of SA added continued to increase,and the tensile strength of the fiber continued to increase.When the SA/PEDOT:PSS mass ratio is 3:1,the tensile strength reached 229±3 MPa,but the elongation basically did not change and remained at 28%.The electrical conductivity of the composite fiber decreases with increasing SA,and the resistance increases from 18±2 k?/cm to 3.5±0.12 M?/cm.The PEDOT:PSS fiber doped with SA has improved elongation and strength,but has poor elastic recovery.Therefore,PEDOT:PSS/PVA composite conductive fibers were prepared in the same mathod by adding a small amount of PVA mainly with PEDOT:PSS.The tensile strength and elongation at break of PEDOT:PSS/PVA fiber increases with the increase of PVA content,and then become larger and smaller.When the PVA content reaches 20wt%,the tensile strength and elongation at break reaches the maximum,it is 176±3.1 MPa and 32±1.7%,and the fiber can be repeatedly stretched under the strain of 10%-20%,and has good elastic recovery.At this time,the electrical resistance of the fiber is 2.2±0.6 M?/cm.In order to improve the conductivity of PEDOT:PSS/PVA fiber,ethylene glycol(EG)was doped in the spinning solution.When the EG doping amount reaches 10wt%,the fiber strength reaches 210±5 MPa,and the electric resistance decreases to 0.6±0.2 M?/cm,the elongation at break is 25%,and stretching can be repeated between 10% and 20% elongation.In this cycle mechanism,the electrical resistance of the composite fiber is proportional to the applied amount.In the repeated stretching of the strain 50 times,the electric resistance was cyclically reciprocated between 0.7-1.1 M?/cm,indicating that the composite fiber can maintain stable conductivity under a certain strain change.The EG-doped PEDOT:PSS/PVA composite fiber can be used to form a conductive loop to illuminate the LED small bulb with the braid and the power source,and has potential applications in the field of smart textiles and wearable devices.